I've been thinking about the Harmony system. Alex and I went on the same bike, me directly after him. He's 25kg lighter than me, and just went round the course with normal riding He came back saying that it was pretty good. I've noticed on my manual Nuvinci that it takes a lot of effort to change down when going up a steep hill (hence the various reported slipping cables). At the test track, I slowed down on the hill to try and make the Harmony change down, but it wouldn't. I'm thinking that the servo doesn't have enough power to change gear under those conditions, i.e. with large force on the chain from the motor plus pedalling going up a steep hill with significant weight. It's probably better with a light rider on a light bike.
